This invention relates to light-emitting semiconductor devices, or light-emitting diodes (LEDs) according to common parlance, which find use in lamps, displays and so forth. More particularly, the invention pertains to light-emitting semiconductor devices made from nitrides and other Groups III-V compound semiconductors, and, still more particularly, to those incorporating an overvoltage protector for saving them from electrical breakdown due to voltage surges. The invention also deals with a method of making such overvoltage-protected light-emitting semiconductor devices.
Light-emitting semiconductor devices made from nitrides and other Groups III-V compound semiconductors are capable of withstanding voltage surges only up to 100 volts or so. These devices were therefore susceptible to breakdown from overvoltages due to static electricity. Japanese Unexamined Patent Publication No. 11-214747 represents a conventional remedy to this problem, teaching an integration of a light-emitting semiconductor device and an overvoltage protector therefor. The specific construction according to this unexamined patent application is a superposition of a flip-chip light-emitting device on a protecting zener diode via a bump electrode.
This known solution is objectionable because of the need for fabrication of the flip-chip light-emitting device and the overvoltage protector independently of each other. Such loose integration of the two functional components made the overvoltage-proof light-emitting device unnecessarily bulky in size and complex and costly in construction.